<?php

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/**
 * CodeIgniter
 *
 * An open source application development framework for PHP 5.1.6 or newer
 *
 * @package CodeIgniter
 * @author ExpressionEngine Dev Team
 * @copyright Copyright (c) 2008 - 2011, EllisLab, Inc.
 * @license http://codeigniter.com/user_guide/license.html
 * @link http://codeigniter.com
 * @since Version 1.0
 * @filesource
 *
 */
    
// ------------------------------------------------------------------------

/**
 * Typography Class
 *
 *
 * @access private
 * @category Helpers
 * @author ExpressionEngine Dev Team
 * @link http://codeigniter.com/user_guide/helpers/
 */
class CI_Typography
{
    
    // Block level elements that should not be wrapped inside <p> tags
    var $block_elements = 'address|blockquote|div|dl|fieldset|form|h\d|hr|noscript|object|ol|p|pre|script|table|ul';
    
    // Elements that should not have <p> and <br /> tags within them.
    var $skip_elements = 'p|pre|ol|ul|dl|object|table|h\d';
    
    // Tags we want the parser to completely ignore when splitting the string.
    var $inline_elements = 'a|abbr|acronym|b|bdo|big|br|button|cite|code|del|dfn|em|i|img|ins|input|label|map|kbd|q|samp|select|small|span|strong|sub|sup|textarea|tt|var';
    
    // array of block level elements that require inner content to be within
    // another block level element
    var $inner_block_required = array(
            'blockquote'
    );
    
    // the last block element parsed
    var $last_block_element = '';
    
    // whether or not to protect quotes within { curly braces }
    var $protect_braced_quotes = FALSE;

    /**
     * Auto Typography
     *
     * This function converts text, making it typographically correct:
     * - Converts double spaces into paragraphs.
     * - Converts single line breaks into <br /> tags
     * - Converts single and double quotes into correctly facing curly quote
     * entities.
     * - Converts three dots into ellipsis.
     * - Converts double dashes into em-dashes.
     * - Converts two spaces into entities
     *
     * @access public
     * @param
     *            string
     * @param
     *            bool whether to reduce more then two consecutive newlines to
     *            two
     * @return string
     */
    function auto_typography ($str, $reduce_linebreaks = FALSE)
    {
        if ($str == '') {
            return '';
        }
        
        // Standardize Newlines to make matching easier
        if (strpos($str, "\r") !== FALSE) {
            $str = str_replace(array(
                    "\r\n",
                    "\r"
            ), "\n", $str);
        }
        
        // Reduce line breaks. If there are more than two consecutive linebreaks
        // we'll compress them down to a maximum of two since there's no benefit
        // to more.
        if ($reduce_linebreaks === TRUE) {
            $str = preg_replace("/\n\n+/", "\n\n", $str);
        }
        
        // HTML comment tags don't conform to patterns of normal tags, so pull
        // them out separately, only if needed
        $html_comments = array();
        if (strpos($str, '<!--') !== FALSE) {
            if (preg_match_all("#(<!\-\-.*?\-\->)#s", $str, $matches)) {
                for ($i = 0, $total = count($matches[0]); $i < $total; $i ++) {
                    $html_comments[] = $matches[0][$i];
                    $str = str_replace($matches[0][$i], '{@HC' . $i . '}', $str);
                }
            }
        }
        
        // match and yank <pre> tags if they exist. It's cheaper to do this
        // separately since most content will
        // not contain <pre> tags, and it keeps the PCRE patterns below simpler
        // and faster
        if (strpos($str, '<pre') !== FALSE) {
            $str = preg_replace_callback("#<pre.*?>.*?</pre>#si", 
                    array(
                            $this,
                            '_protect_characters'
                    ), $str);
        }
        
        // Convert quotes within tags to temporary markers.
        $str = preg_replace_callback("#<.+?>#si", 
                array(
                        $this,
                        '_protect_characters'
                ), $str);
        
        // Do the same with braces if necessary
        if ($this->protect_braced_quotes === TRUE) {
            $str = preg_replace_callback("#\{.+?\}#si", 
                    array(
                            $this,
                            '_protect_characters'
                    ), $str);
        }
        
        // Convert "ignore" tags to temporary marker. The parser splits out the
        // string at every tag
        // it encounters. Certain inline tags, like image tags, links, span
        // tags, etc. will be
        // adversely affected if they are split out so we'll convert the opening
        // bracket < temporarily to: {@TAG}
        $str = preg_replace("#<(/*)(" . $this->inline_elements . ")([ >])#i", 
                "{@TAG}\\1\\2\\3", $str);
        
        // Split the string at every tag. This expression creates an array with
        // this prototype:
        //
        // [array]
        // {
        // [0] = <opening tag>
        // [1] = Content...
        // [2] = <closing tag>
        // Etc...
        // }
        $chunks = preg_split('/(<(?:[^<>]+(?:"[^"]*"|\'[^\']*\')?)+>)/', $str, 
                - 1, PREG_SPLIT_DELIM_CAPTURE | PREG_SPLIT_NO_EMPTY);
        
        // Build our finalized string. We cycle through the array, skipping
        // tags, and processing the contained text
        $str = '';
        $process = TRUE;
        $paragraph = FALSE;
        $current_chunk = 0;
        $total_chunks = count($chunks);
        
        foreach ($chunks as $chunk) {
            $current_chunk ++;
            
            // Are we dealing with a tag? If so, we'll skip the processing for
            // this cycle.
            // Well also set the "process" flag which allows us to skip <pre>
            // tags and a few other things.
            if (preg_match("#<(/*)(" . $this->block_elements . ").*?>#", $chunk, 
                    $match)) {
                if (preg_match("#" . $this->skip_elements . "#", $match[2])) {
                    $process = ($match[1] == '/') ? TRUE : FALSE;
                }
                
                if ($match[1] == '') {
                    $this->last_block_element = $match[2];
                }
                
                $str .= $chunk;
                continue;
            }
            
            if ($process == FALSE) {
                $str .= $chunk;
                continue;
            }
            
            // Force a newline to make sure end tags get processed by
            // _format_newlines()
            if ($current_chunk == $total_chunks) {
                $chunk .= "\n";
            }
            
            // Convert Newlines into <p> and <br /> tags
            $str .= $this->_format_newlines($chunk);
        }
        
        // No opening block level tag? Add it if needed.
        if (! preg_match("/^\s*<(?:" . $this->block_elements . ")/i", $str)) {
            $str = preg_replace("/^(.*?)<(" . $this->block_elements . ")/i", 
                    '<p>$1</p><$2', $str);
        }
        
        // Convert quotes, elipsis, em-dashes, non-breaking spaces, and
        // ampersands
        $str = $this->format_characters($str);
        
        // restore HTML comments
        for ($i = 0, $total = count($html_comments); $i < $total; $i ++) {
            // remove surrounding paragraph tags, but only if there's an opening
            // paragraph tag
            // otherwise HTML comments at the ends of paragraphs will have the
            // closing tag removed
            // if '<p>{@HC1}' then replace <p>{@HC1}</p> with the comment, else
            // replace only {@HC1} with the comment
            $str = preg_replace(
                    '#(?(?=<p>\{@HC' . $i . '\})<p>\{@HC' . $i .
                             '\}(\s*</p>)|\{@HC' . $i . '\})#s', 
                            $html_comments[$i], $str);
        }
        
        // Final clean up
        $table = array(
                
                // If the user submitted their own paragraph tags within the
                // text
                // we will retain them instead of using our tags.
                '/(<p[^>*?]>)<p>/' => '$1', // <?php BBEdit syntax coloring bug
                                            // fix
                                            
                // Reduce multiple instances of opening/closing paragraph tags
                                            // to a single one
                '#(</p>)+#' => '</p>',
                '/(<p>\W*<p>)+/' => '<p>',
                
                // Clean up stray paragraph tags that appear before block level
                // elements
                '#<p></p><(' . $this->block_elements . ')#' => '<$1',
                
                // Clean up stray non-breaking spaces preceeding block elements
                '#(&nbsp;\s*)+<(' . $this->block_elements . ')#' => '  <$2',
                
                // Replace the temporary markers we added earlier
                '/\{@TAG\}/' => '<',
                '/\{@DQ\}/' => '"',
                '/\{@SQ\}/' => "'",
                '/\{@DD\}/' => '--',
                '/\{@NBS\}/' => '  ',
                
                // An unintended consequence of the _format_newlines function is
                // that
                // some of the newlines get truncated, resulting in <p> tags
                // starting immediately after <block> tags on the same line.
                // This forces a newline after such occurrences, which looks
                // much nicer.
                "/><p>\n/" => ">\n<p>",
                
                // Similarly, there might be cases where a closing </block> will
                // follow
                // a closing </p> tag, so we'll correct it by adding a newline
                // in between
                "#</p></#" => "</p>\n</"
        );
        
        // Do we need to reduce empty lines?
        if ($reduce_linebreaks === TRUE) {
            $table['#<p>\n*</p>#'] = '';
        } else {
            // If we have empty paragraph tags we add a non-breaking space
            // otherwise most browsers won't treat them as true paragraphs
            $table['#<p></p>#'] = '<p>&nbsp;</p>';
        }
        
        return preg_replace(array_keys($table), $table, $str);
    }
    
    // --------------------------------------------------------------------
    
    /**
     * Format Characters
     *
     * This function mainly converts double and single quotes
     * to curly entities, but it also converts em-dashes,
     * double spaces, and ampersands
     *
     * @access public
     * @param
     *            string
     * @return string
     */
    function format_characters ($str)
    {
        static $table;
        
        if (! isset($table)) {
            $table = array(
                    // nested smart quotes, opening and closing
                    // note that rules for grammar (English) allow only for two
                    // levels deep
                    // and that single quotes are _supposed_ to always be on the
                    // outside
                    // but we'll accommodate both
                    // Note that in all cases, whitespace is the primary
                    // determining factor
                    // on which direction to curl, with non-word characters like
                    // punctuation
                    // being a secondary factor only after whitespace is
                    // addressed.
                    '/\'"(\s|$)/' => '&#8217;&#8221;$1',
                    '/(^|\s|<p>)\'"/' => '$1&#8216;&#8220;',
                    '/\'"(\W)/' => '&#8217;&#8221;$1',
                    '/(\W)\'"/' => '$1&#8216;&#8220;',
                    '/"\'(\s|$)/' => '&#8221;&#8217;$1',
                    '/(^|\s|<p>)"\'/' => '$1&#8220;&#8216;',
                    '/"\'(\W)/' => '&#8221;&#8217;$1',
                    '/(\W)"\'/' => '$1&#8220;&#8216;',
                    
                    // single quote smart quotes
                    '/\'(\s|$)/' => '&#8217;$1',
                    '/(^|\s|<p>)\'/' => '$1&#8216;',
                    '/\'(\W)/' => '&#8217;$1',
                    '/(\W)\'/' => '$1&#8216;',
                    
                    // double quote smart quotes
                    '/"(\s|$)/' => '&#8221;$1',
                    '/(^|\s|<p>)"/' => '$1&#8220;',
                    '/"(\W)/' => '&#8221;$1',
                    '/(\W)"/' => '$1&#8220;',
                    
                    // apostrophes
                    "/(\w)'(\w)/" => '$1&#8217;$2',
                    
                    // Em dash and ellipses dots
                    '/\s?\-\-\s?/' => '&#8212;',
                    '/(\w)\.{3}/' => '$1&#8230;',
                    
                    // double space after sentences
                    '/(\W)  /' => '$1&nbsp; ',
                    
                    // ampersands, if not a character entity
                    '/&(?!#?[a-zA-Z0-9]{2,};)/' => '&amp;'
            );
        }
        
        return preg_replace(array_keys($table), $table, $str);
    }
    
    // --------------------------------------------------------------------
    
    /**
     * Format Newlines
     *
     * Converts newline characters into either <p> tags or <br />
     *
     * @access public
     * @param
     *            string
     * @return string
     */
    function _format_newlines ($str)
    {
        if ($str == '') {
            return $str;
        }
        
        if (strpos($str, "\n") === FALSE &&
                 ! in_array($this->last_block_element, 
                        $this->inner_block_required)) {
            return $str;
        }
        
        // Convert two consecutive newlines to paragraphs
        $str = str_replace("\n\n", "</p>\n\n<p>", $str);
        
        // Convert single spaces to <br /> tags
        $str = preg_replace("/([^\n])(\n)([^\n])/", "\\1<br />\\2\\3", $str);
        
        // Wrap the whole enchilada in enclosing paragraphs
        if ($str != "\n") {
            // We trim off the right-side new line so that the closing </p> tag
            // will be positioned immediately following the string, matching
            // the behavior of the opening <p> tag
            $str = '<p>' . rtrim($str) . '</p>';
        }
        
        // Remove empty paragraphs if they are on the first line, as this
        // is a potential unintended consequence of the previous code
        $str = preg_replace("/<p><\/p>(.*)/", "\\1", $str, 1);
        
        return $str;
    }
    
    // ------------------------------------------------------------------------
    
    /**
     * Protect Characters
     *
     * Protects special characters from being formatted later
     * We don't want quotes converted within tags so we'll temporarily convert
     * them to {@DQ} and {@SQ}
     * and we don't want double dashes converted to emdash entities, so they are
     * marked with {@DD}
     * likewise double spaces are converted to {@NBS} to prevent entity
     * conversion
     *
     * @access public
     * @param
     *            array
     * @return string
     */
    function _protect_characters ($match)
    {
        return str_replace(array(
                "'",
                '"',
                '--',
                '  '
        ), array(
                '{@SQ}',
                '{@DQ}',
                '{@DD}',
                '{@NBS}'
        ), $match[0]);
    }
    
    // --------------------------------------------------------------------
    
    /**
     * Convert newlines to HTML line breaks except within PRE tags
     *
     * @access public
     * @param
     *            string
     * @return string
     */
    function nl2br_except_pre ($str)
    {
        $ex = explode("pre>", $str);
        $ct = count($ex);
        
        $newstr = "";
        for ($i = 0; $i < $ct; $i ++) {
            if (($i % 2) == 0) {
                $newstr .= nl2br($ex[$i]);
            } else {
                $newstr .= $ex[$i];
            }
            
            if ($ct - 1 != $i)
                $newstr .= "pre>";
        }
        
        return $newstr;
    }
}
// END Typography Class

/* End of file Typography.php */
/* Location: ./system/libraries/Typography.php */